The purpose of the proposed research is to determine the organization of the functional anatomy of the central regulation of the anterior pituitary. Our research involves a topographical study of the location of releasing factor containing neuronal perikarya and the pathways by which their axons reach the median eminence. In addition, other studies are focused upon the quantitative investigation of dopaminergic, noradrenergic, serotonergic, cholinergic and gabaminergic fiber inputs to the medial basal hypothalamus and anterior hypothalamus. In addition, we are investigating the effects of changes in the endocrine milieu and the administration of neuroleptic drugs on the kinetic properties of tyrosine hydroxylase and on the rates of synthesis of catecholamine neurotransmitters. Other studies involve investigation of specific lesions of various neuronal inputs to the hypothalamus on central neuroendocrine regulation. Finally we have begun investigations of the use of drugs which appear to be specifically cytotoxid for neuronal perikarya as tools for determining the origin of specific fiber inputs to the diencephalon of the rat. It is hoped that these several approaches will enable us to determine which specific neuronal inputs, under what circumstances, and in what area of brain regulates each separate endocrine function. BIBLIOGRAPHIC REFERENCES: Carson, K., Nemeroff, C.B., Rone, M.S., Youngblood, W.W., Hanker, J.S. and Kizer, J.S. Biochemical and histochemical evidence for a tuberoinfundibular cholinergic pathway. Brain Research, (in press) 1977. Kizer, J.S. and Youngblood, W.W. Neurotransmitter regulation of neuroendocrine secretion in: Psychopharmacology: A Generation of Progress; Lipton, DiMascio, Killam (eds), Raven Press, N.Y., 1977 (in press).